In Pactio all players build the same city. However as all of the players get different roles, they might have different agendas, and ideas for the city.
The game center point is buying buildings and developing them, as they often synergise with themselves, or your role. They also serve as your source of income to fuel your actions for the future. In addition players influence public figures and/or make deals with each other to further aid your goal.
The goal of the game is to get the most victory points by the end of 16-th turn, that is when the game ends. You gain them, again, from buildings, but also from role's missions, which might be related to buildings, but might be completely unique things. For example Pishop gets 5 Victory points if all other players' final scores are not too far apart (difference can't be bigger than 6).
Unique aspects of the game include that all deals are binding, meaning they are enforced by the game rules. Also the implementation of roles in an economical environment leads to loads of new and very interesting gameplay.